Jolteon, The Lightning Pokémon. If it is angered or startled, the fur all over its body bristles like sharp needles that pierce foes. It accumulates negative ions in the atmosphere to blast out 10,000.volt lightning bolts. It easily becomes sad or angry. Every time its mood changes, it charges power. Every hair on its body starts to stand sharply on end if it becomes charged with electricity. The negatively charged ions generated in its fur create a constant sparking noise. It's cells generate a low level of electricity. This power is amplified by the static electricity of its fur, enabling it to drop thunderbolts.

With a base speed of 130 (and a potential 394 final
speed stat), Jolteon can and will outrun most pokemon.
It should be able to outrun Aerodactyl (assuming it
doesn't have a +speed nature and 252 speed EV's), it
should be able to KO it with ease (Thunderbolt) before
getting hit by an Earthquake.
Since the main type of Pokemon Jolteon has to be
careful of are Ground types or Pokemon that can learn
Earthquake, Jolteon should at least have Hidden Power
Ice. This takes care of most ground types (apart from
pokemon like Swampert, hence the reason HP Grass was
included) and Salamence (which is usually carrying
Earthquake)
For Hidden Power Ice, I suggest these IV placements:
31/02/30/31/31/31 and for Hidden Power grass:
31/03/30/31/30/31.
Jolteon can set up a fast substitute to protect
against Status damage or attack damage. Prediction
helps too, especially if you know your opponent plans
to use an Electric attack against one of your current
pokemon, then you can switch to Jolteon and it will
regain 1/4 of its HP (making up for the loss in a
substitute).
Thunderwave and Baton pass are pretty obvious choices
(stall with Thunderwave, Baton pass in case of Arena
traps/Mean look pokemon), so use either one if you
know for sure what your opponent intends to use in his
team.

EV Corner:

Max out the EVs in Speed and Special Attack for Jolteon with any remaining in HP

Strategy Against Jolteon

Jolteon is one of the four (three not counting Mewtwo)
Base 130 Speed Pokémon, Base 130 being the fourth
highest Base Speed in the game. Jolteon has a good
Special Attack stat to go with it alongside a
respectable Special Defense.
- Firstly, don't try to catch it with a status unless
you are using something faster (such as Electrode,
Electrode with Thunder Wave could spell an end to
Jolteon - just so you know), since most Jolteons will
just set up a Sub on the first turn and block your
status.
- Also, don't expect to keep Jolteon trapped via
Dugtrio's (or Trapinch's) Arena Trap. Although not all
Jolteons carry it, some do have Baton Pass, which will
allow them to escape their situation. Same goes for
using Mean Look on it.
- Prediction is your friend when you know your
opponent has a Jolteon. If he has something weak to
Electric attacks and knows you have an Electric
attack, he'll more than likely switch to Jolteon who
will gain back a Ľ of its lost HP (the equivalent of
what it loses with Sub).
- "Always strikes first" style moves are always a good
thing against something as fast (and as weak
defensively) as Jolteon, since you'll definitely score
some decent damage (hopefully by surprise).
- If you want to take down Jolteon your best bet is
surprise. If you can catch it with EQ while it
switches in you will most likely have a KO. Jolteon
will simply Sub before you attack and since you
(probably) can't Taunt before it uses it, you are
forced to whittle down its HP by forcing it to re-Sub
until it is forced to switch or take the hit.

Contest Moveset

A good Contest Moveset for Jolteon would have to be this for the Cool Contest best with Lonely, Adament, Naughty or Brave Nature:

Attacks:

Rain Dance
Thunderbolt
Thunderwave
Hyper Beam

Items Attached:

Red Scarf

Strategy Using Jolteon

If you do the attacks in this following order you should have very few problems; 1st - Rain dance, 2nd - Thunderbolt, 3rd - Rain
dance, 4th - Thunderbolt, 5th - Hyper beam/Thunderwave

Locations in Games

Ruby/Sapphire/Emerald

Trade from FR/LG

Colosseum

Trade from FR/LG

Fire Red/Leaf Green

Evolve Eevee

Animé Appearences

Jolteon has had a few Animé Appearences. First it was owned by one of the Eevee brothers. After that, Ash battled one in the Pokemon League Entrance Exam. After that one of the Kimono Sisters in Ecruteak City had one. The Rest are Cameos